//
// Created by Administrator on 2024/3/25.
//
#include<bits/stdc++.h>

using namespace std;
const int maxn = 100;
using ll = long long;
vector<vector<ll>> dp(maxn, vector<ll>(maxn, 0ll));//STL定义二维数组的常用技巧

void init() {
    for (int i = 0; i < maxn; i++) {
        dp[i][0] = dp[i][i] = 1;
    }
    for (int i = 2; i < maxn; i++) {
        for (int j = 1; j < i; j++) {
            dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j];
        }
    }
}

int main() {
    init();
    for (int m, n; cin >> m >> n;) {
        cout << dp[m][n] << endl;
    }

    return 0;
}
